Simulation of hydrogen and hydrogen-assisted propane ignition in pt catalyzed microchannel

Seshadri, Vikram; Kaisare, Niket S.

doi:10.1016/j.combustflame.2010.04.005

Cited by 30 publications

(11 citation statements)

References 32 publications

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“…Methane results were excluded from Figure 4 because only a single catalytic cycle was observed at the higher flow rate of 1000 mL/min. The need for thermal activation for these fuels is in agreement with similar studies of various Pt catalytic combustion systems [12,19,21,28,30,31,41]. Figure 4 shows catalytic cycling and relatively constant peak temperatures for propane and butane fuels consistent with previous methanol studies.…”

Section: Alternative Fuel Studysupporting

confidence: 86%

“…As the resulting glow suggests, heat generation is concentrated in the center core of the substrate; subsequent temperature measurements at radial locations have indicated <10% drop in average temperatures from the substrate center. This is in contrast to the axial locations that demonstrate a more dramatic reduction of ∼35% in temperature when inlet temperatures are compared to the outlet temperatures within the center channel, a feature that is common with low conductivity substrates [31]. While thermal map of the substrate is sufficiently described here, additional temperature and ignition time mapping studies are reported elsewhere [51].…”

Section: Alternative Fuel Studymentioning

confidence: 95%

“…Further enhancements in reactivity can be achieved by alloyed or supported catalysts [26][27][28][29][30]. With respect to the choice of fuels, typically small hydrocarbon fuels or hydrogen [10,31,32] has been studied. Hydrocarbon fuels studied include commercially available alkanes such as methane [12,14,27,33,34], propane [11,21,28,30,35], and butane [36][37][38] and simple alcohols such as methanol [29,39,40] and ethanol [17,41,42].…”

Section: Introductionmentioning

confidence: 99%

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A Study of Fuel and Reactor Design for Platinum Nanoparticle Catalyzed Microreactors

McNally

Agnello

Pastore

et al. 2015

Journal of Nanomaterials

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Typical microcombustion-based power devices entail the use of catalyst to sustain combustion in less than millimeter scale channels. This work explores the use of several other candidate fuels for ~8 nm diameter Pt particle catalyzed combustion within 800 μm channel width cordierite substrates. The results demonstrate while commercial hydrocarbon fuels such as methane, propane, butane, and ethanol can be used to sustain catalytic combustion, room temperature ignition was only observed using methanol-air mixtures. Fuels, other than methanol, required preheating at temperatures >200°C, yet repeated catalytic cycling similar to methanol-air mixtures was demonstrated. Subsequently, a new reactor design was investigated to couple with thermoelectric generators. The modified reactor design enabled ignition of methanol-air mixtures at room temperature with the ability to achieve repeat catalytic cycles. Preliminary performance studies achieved a maximum temperature differenceΔTof 55°C with a flow rate of 800 mL/min. While the temperature difference indicates a respectable potential for power generation, reduced exhaust temperature and improved thermal management could significantly enhance the eventual device performance.

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Section: Alternative Fuel Studysupporting

confidence: 86%

Section: Alternative Fuel Studymentioning

confidence: 95%

Section: Introductionmentioning

confidence: 99%

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A Study of Fuel and Reactor Design for Platinum Nanoparticle Catalyzed Microreactors

McNally

Agnello

Pastore

et al. 2015

Journal of Nanomaterials

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“…Promoting front-end ignition was shown to provide faster ignition and lower propane emissions [30]. Seshadri and Kaisare [31] showed similar transient behavior for hydrogen-assisted propane ignition in co-feed and sequential feeding modes. Ignition of fuel mixtures in catalytic microburners showed sequential ignition of fuels: the fuel with lower ignition temperature ignited first, followed by ignition of the other fuel [31,32].…”

Section: Introductionmentioning

confidence: 91%

The Role of Homogeneous Chemistry during Ignition of Propane Combustion in Pt-Catalyzed Microburners

Regatte

Selle

Kaisare

2012

International Journal of Spray and Combustion Dynamics

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The aim of this work is to numerically investigate the ignition behavior of homogeneousheterogeneous (HH) combustion of propane in a Pt-catalyzed microburner to delineate the role of homogeneous chemistry during cold-start ignition. A two dimensional model with one-step homogeneous and catalytic mechanisms in a parallel-plate microburner is considered. The ignition characteristics (ignition temperature and ignition time) are explored for catalytic microreactor with and without homogeneous chemistry. We show that the catalytic reaction lights-off first, followed by the homogeneous reaction. Consequently, the homogeneous chemistry does not affect the ignition behavior of the catalytic microburner. The effect of inlet velocity, wall thermal conductivity and gap size on ignition characteristics is explored. The ignition characteristics are not affected by homogeneous chemistry even at larger gap sizes, despite the fact that the homogeneous contribution at steady state increases with increasing gap size of the microburner.

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“…Hydrogen is currently investigated as a fuel for large power plants − and for microreactors in small-scale power generation. − Hydrogen in small power systems can be prepared on-board from hydrocarbons using microreformers. , While catalytic combustion is a choice for large power plants, ,, it is the mainstream approach for small power systems. This is primarily due to the increased surface-to-volume ratios of microreactors that promote surface catalytic reactions over volumetric gas-phase reactions.…”

Section: Introductionmentioning

confidence: 99%

Impact of Gaseous Chemistry in H₂–O₂–N₂ Combustion over Platinum at Fuel-Lean Stoichiometries and Pressures of 1.0–3.5 bar

et al. 2017

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The catalytic and gas-phase combustion of fuel-lean H2–O2–N2 premixtures was investigated in a channel coated with platinum at pressures 1.0–3.5 bar, a range encompassing microreactors in portable power generation systems and passive hydrogen recombiners in nuclear power plants. One-dimensional Raman spectroscopy assessed the progress of catalytic hydrogen combustion, while planar laser-induced fluorescence (LIF) of the hydroxyl radical monitored gaseous combustion. Simulations were performed using a 2-D code with detailed catalytic and gas-phase reaction mechanisms and realistic transport. Both LIF measurements and simulations revealed that homogeneous combustion was vigorously sustained below ∼2.5 bar, while it was effectively suppressed at higher pressures. This was due to the intricate pressure dependency of the hydrogen gaseous ignition chemistry and the competition between catalytic and gaseous chemical reactions for hydrogen consumption. Parametric simulations determined the smallest critical channel heights allowing for appreciable gaseous combustion and their dependency on pressure, wall temperature, and inlet velocity. It was shown that for the narrower channels of catalytic microreactors homogeneous combustion was relevant only for wall temperatures above 1300 K, whereas for the wider hydrogen recombiner channels it could be relevant for wall temperatures down to 1100 K. Furthermore, at 1100 K the critical channel heights were nonmonotonic functions of pressure, reaching their peaks at 2.0–2.5 bar.

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Simulation of hydrogen and hydrogen-assisted propane ignition in pt catalyzed microchannel

Cited by 30 publications

References 32 publications

A Study of Fuel and Reactor Design for Platinum Nanoparticle Catalyzed Microreactors

A Study of Fuel and Reactor Design for Platinum Nanoparticle Catalyzed Microreactors

The Role of Homogeneous Chemistry during Ignition of Propane Combustion in Pt-Catalyzed Microburners

Impact of Gaseous Chemistry in H₂–O₂–N₂ Combustion over Platinum at Fuel-Lean Stoichiometries and Pressures of 1.0–3.5 bar

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Simulation of hydrogen and hydrogen-assisted propane ignition in pt catalyzed microchannel

Cited by 30 publications

References 32 publications

A Study of Fuel and Reactor Design for Platinum Nanoparticle Catalyzed Microreactors

A Study of Fuel and Reactor Design for Platinum Nanoparticle Catalyzed Microreactors

The Role of Homogeneous Chemistry during Ignition of Propane Combustion in Pt-Catalyzed Microburners

Impact of Gaseous Chemistry in H2–O2–N2 Combustion over Platinum at Fuel-Lean Stoichiometries and Pressures of 1.0–3.5 bar

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Impact of Gaseous Chemistry in H₂–O₂–N₂ Combustion over Platinum at Fuel-Lean Stoichiometries and Pressures of 1.0–3.5 bar